Sleeper beam

In prehistoric, Roman, Saxon and medieval timber-framed buildings, the framing was often erected not on a wall foundation but directly on a horizontal beam resting on or slightly recessed into the ground. From its recumbent position this is known as a sleeper beam. Though very rarely surviving, its wood will often leave a dark stain in the ground detectable by careful excavation. Little Marlow Priory had a sleeper wall, a similar feature but a stone wall resting on the ground.